Signal phasing system



April 5, 1960 o. A. JoRGENsEN 932912 SIGNAL PHASING SYSTEM Filed April15, 1959 2 sheets-sheet 1 OTTO A. JORGENSEN F|G.3 Y @M599 ATTORNEY April5, 1960 o. A. JoRGENsEN 2,932,012

SIGNAL PHASING SYSTEM Filed April 15. 1959 2 sheets-sheet 2 SIGNALPnAsnsG SYSTEM Otto A. Jorgensen, Pittsford, N.Y., assigner to GeneralDynamics Corporation, Rochester, N.Y., a corporation Y of DelawareApplication April 15, 1959, Serial No. 806,717 12 Claims. (Cl. 340-174)My invention relates generally to a system for phasing signals, i.e.,for shifting signals into a definite relationship with respect to aparticular time base.

In the past, apparatus has been provided for feeding signals occuring atrandom times into a system which requires that such input signals occurat regular intervals with respect to a time base. Such apparatus usuallyhas employed a memory unit or units capable of accepting and storingeach random-time input signal. The apparatus also has included meansperiodically operated from a clock, which defines the aforementionedtime base, for applying readout signals to the memory units and therebyproducing signals at the output of the apparatus which are in therequired time position. Such output signals then may be applied tosucceeding equipment for utilization.

The use of such apparatus presupposes that the memory units therein arecapable of accepting input signals occurring at any time. However, somememory devices,

such as parametrically-excited resonators, do not have such acapability, but accept signals only when separate excitation signals areapplied thereto, the memory dev vices being unresponsive to inputsignals applied at other times. Because the last-named type of memorydevices has other features which may make their use in a signal phasingor rephasing system particularly apt, it is therefore desirable toprovide a system by which randomlyoccurring signals may be written intoat least one of the memory units which are capable only when excited ofaccepting such signals.

Accordingly, it is an object of my invention to provide a new andimproved system for phasing or rephasing electrical signals.

Another object of my invention is to provide new and improved apparatusfor controlling the phasing of signals wherein the memory units acceptsignals only upon the regular reoccurrence of exciting signals.

Another object of my invention is to provide new and improved apparatusfor controlling the phasing of signals wherein the memory units acceptsignals only upon the application of exciting signals thereto.

Another object of my invention is to provide new and improved apparatusfor phasing signals employing parametrically-excited resonators asstoring units.

I accomplish these and other objects in a system having a source capableof producingV signals of uniform duration which may occur at randomtimes. A shift register is provided having a plurality fof memoryelements disposed in a series, each of the elements having a iirstsignal input, an exciting input and an output, and each of theintermediate and last of the elements in the series having a secondsignal input. The elements of the series Vare arranged in such a mannerthat the output of each of the first and intermediate ones of theelements are coupled to the second signal input of the next succeedingone of the series elements. The output of the last series element alsoserves as an output for the register. The

2932,01? Patented Apr. 5, 1960 elements of the register are chosen to beresponsive to the application of a signal to either of its signal inputsand to the exciting input for producing a signal on the output of thatelement only for the duration of the signal applied to the excitinginput. An example of such an element is a parametrically-excitedresonator, which is understood by those skilled in the art.

In order to lsupply signals to the exciting inputs of the variouselements, VI provide driving means having outputs coupled toaforementioned exciting inputs of individual ones of the registerelements and effective for supplying thereover signals in regularlyrecurring sequence, starting at the first of the register elements andproceeding element by element vthrough the register to the last. Eachsuch exciting signal produced by the driving means slightly overlaps intime the exciting signals occuring immediately before and thereafter andthe lastoccurring exciting signal in each frame overlaps in time thefirst-occurring signal in the nextl frame. Each exciting signal is thesame or greater duration as the signals supplied by the aforementionedrandom time signal source. With this arrangement, any signal occurring(i.e.,

an information bit stored) in one of the elements is advanced from thatelement through the succeeding element in series and ultimately isproduced at the register output as a useful signal in synchronism withthe regularly occurring exciting signal applied to the'last element ofthe series.

In order to provide an input signal for any one of the elements, Ifurnish a plurality of signal producing means which correspond in numberto the number of elements in the register. Each signal producing meansis operative for generating signals in coincidence with the signalsapplied to the exciting input of the element to which the individualsignal producing means corresponds. A plurality `of gates, each of whichis individual to one of the signal producing means and register elementsare provided, each gate being used for coupling the corresponding signalproducing means to the first signal input of the next succeeding memoryelement in the aforementioned series. Each gate has a control input andis operative only in response to the application of a signal thereto forpassing signals from its signal producing means to its register element.v

In order to control the gates, and therefore the admission of signals tothe various register element inputs, I provide means for coupling therandom time signal source to the control inputs of all theaforementioned gates. With this arrangement, a randomly-occuring signalapplied to the control input of any one of the gates must occur in atime position which corresponds to the time position of at least one ofthe signals applied to the exciting inputs of the register elements.Therefore, an information bit is inserted at that time within one of theregister elements and subsequently is advanced toward and arrives at theregister output in coincidence with the excitation of the last elementwithin the register. This rephased signal, occurring only when the lastregister element is excited, can thereafter be utilized within other,succeeding equipment. Y

In the description of the preferred embodiment of my invention whichfollows, reference is made to the drawings attached to' and forming apart of the present speciii- The memoryiunits or elements used in thepreferred June, 1955. In order to simplify thevdescription of theVpreferred embodiment of my invention, which employs many suchresonators, I next describethe operation of a singleparametrically-excited resonator, it being understood that allVresonators later referred to in this description function 'insubstantially the same manner.

Fig. l shows a parametrically-excited resonator. A tank circuitin theresonatorV includes an inductance element consisting ofseries-connected, substantially electrically-equal windings 1a and 2a oftransformers 1 and 2, respectively, and capacitor 3 coupled in parallelwith the inductive element. ACapacitor 3 and the inductance element arechosen to make the tank circuit resonate at a particular frequency.

In order to excite the tank circuit, means including continuouslyoperating generator 13 coupled in series with a blocking capacitor isconnected through exciting signal input terminal 6 to the transformer 1and 2 secondary windings 1b and 2b, which are substantially equal toeach other in the electrical sense and are connected in seriesopposition with respect to windingsY 1a and 2.a. Generator 13 isselected so that its output signal is twice the resonant frequency ofthe above-described tank. Tne tank circuit exciting means also includesseries-connected battery 12 and variable resistor 11 coupled in serieswith windings 1b and 2b, the direct current llow from battery 12 beingadjusted to the point where the flux density in the cores oftransformers 1 and 2 is just less than saturation. With thisarrangement, the small, periodic changes in current within windings 1band 2b of transformers 1 and 2 caused by generator 13 are effective forrepeatedly driving the cores of transformers 1 and 2 betweennonsaturated and saturated conditions, so that the inductance presentedby windings 1a and 2a changes at frequency of the signals produced bygenerator 13. Since windings 1b and 2b are connected in opposition toeach other with respect to windings 1a and 1b, no signal from generator13 is detectable across the aforementioned tank and output terminal 7,which is connected across the tank. In the absence of an external signalapplied across the aforementioned tank, the tank circuit does notresonate under the influence of signals applied to its excitation inputfrom generator 13.

In order to start production of a signal in the parametrically-excitedresonator, a plurality of signal inputs, such as terminal 4 andseries-connected resistor 8, are provided. A momentary,ground-referenced signal of frequency substantially equal to theresonant frequency of the tank circuit from a source (not shown) appliedto terminal 4 is coupled to the tank circuit by resistor 8.

resonator. It is to be seen, at the left-hand end of the Fig. 3h signalcurve, that the small resonant frequency signal cross the tank circuitand resonator output, which occurs when a resonant frequency signal isapplied to terminal 4, is built up within the tank circuit to 4a maximumupon and subsequent to the occurrence of the exciting signal on terminal6. The output signal is thereafter maintained at the maximum level untilthe Fig. 3b exciting signal is removed from terminal 6, and, upon thedisappearanceofr the exciting signal,.the output' signal decays'to zero.

Before leaving the consideration of the individualparametrically-excited resonator, it is pointed out that the resonatoris bistable in the sense that it is capable of producing either first orsecond signals which are 180 degrees out-of-phase with each other whenthe phase of the input signal is regularly related to the phase of theexciting signal. The phase of the output signal appearing at terminal 7(Fig. 3h) is the same phase as the input signalapplied to terminal 4(Fig. 3f). In Fig. 3f, the solid and broken signal curves represent rstand second possible output signals at terminal 7. Thus, it is to be seenthat by selectively applying to terminal 4 signals in 0 or 1r phase withreference to each other (represented by solid and broken lines,respectively), 0 or rr phase signals can be taken off at the output. Itis this bistable characteristic which makes the parametrically-excitedresonator par-y Y ticularly suited to my invention which is describedbelow.

If no exciting signal is being applied to the tank circuit when a startsignal is applied to terminal 3, the resonant frequency signal withinthe tank decays to zero subsequent to the removal of the start signalfrom terminal 4. However, application of a resonant frequency signal toterminal 4 when an exciting signal is present on terminal 6 causes asignal to be built up within the tank circuit by virtue of theabove-described changes in the value of the tankA circuit inductiveelement. This built-up signal directly coupled' to the'resonator output,which includes terminal 7, is continued subsequent to the removal ofthev start signal from-terminal 4 anduntilthe excitingy signal isremoved from terminal 4.

The relationship among input, exciting, and output signals is bestdemonstrated by comparing Figs. 3b, 3f vand 3h which may be consideredto represent the exciting and input signals applied to terminals 6 and 4and the output signal measured at terminal 7, respectively, of the Fig.1

In the description which follows, the 0 and 1r phase signals may beconsidered as 0 and l outputs, respectively, of eachparametrically-excited resonator.

In order to simplify the Fig. 4 schematic drawing of the systemrepresenting my invention and the description thereof, each of theseveral parametrically-excited resonators is represented by a circle, itbeing understood that all resonators function in substantially the samemanner as the one described above. the circular symbols representingparametrically-excited vresonators also have lines extending radiallytherefrom.

Such radial lines have arrows pointing toward the circle and representsignal inputs, such as the one including terminal 4 in the abovedescribed Fig. l resonator. Similarly, a radial line having an arrowpointing away from the circle is used to represent an output, such asthe one including terminal 7 in the Fig. l resonator. A radial linerunning into the circle and bearing no arrow is used for representingthe exciting input of the resonator.

Referring to the system shown in Fig. 4, I provide a source 40 capableof generating signals of substantially uniform duration at random times.Source 4t) is coupled to the input of delay multivibrator 41 wherein thesignals incoming from source 40 are shaped and reduced to signals ofuniform width and which appear on output conductor 41a. The nextdescribed apparatus is directed to rephasing or shifting each suchrandomly-occurring signal into coincidence with one of regularlyrecurringl reference signals.

In order to receive signals triggered by delay multivibrator 41, Iprovide a shift register comprising first, second and thirdparametrically-excited esonators 42, 43 and v44, respectively, tuned toresonate at the same particular of they succeeding (or intermediate) and.last Yof the l parametric resonators 43 and 44 in the series. Each ,ofresonators 42, 43 and-44 has a second. input 42e, 43cand 44e,respectively, the use of which is to beexplained presently. At thistime, it is pointed out that output 44h of resonator 44 represents theoutput of the system, that thesystenr normally is tov be effective forregularly. pro,-

Referring to Figs. 2a and 2b,l

assauts U ducing O signals, and that the system is to substitute a 1rphase or l signal for the one of the signals in response to theappearance of a signal on conductor 41a.

Each resonator is further provided with an exciting input 42d, 43d and44d. In order to excite each resonator 42, 43 and 44 sequentially and inthe order named, I provide a clock 45 for producing a continuoussinusoidal signal at twice the resonant frequency of resonators 42, 43and 44. T-he output of clock 45 is connected to the input of signaldistributor 46. Distributor 46 has iirst, second and third outputs 47,48 and 49 and is effective -for admitting signals from clock 45 to thoseconductors in the order named and in the relationship indicated in Figs.3a, 3b and 3c, respectively. The operation of distributor 46 is suchthat the signal appearing on any one of conductors 47, 48 or 49 slightlyoverlaps the signals present on the others of the conductors. Conductors47,- 48 and 49 are connected to the excitation inputs 44d, 42d, and 43d,respectively. In this manner, each of resonators 42, 43 and 44 isperiodically fed an exciting signal which slightly overlaps theexcitation signals applied to the next preceding and next succeeding oneof the series of resonators.

In order to supply 0 signals to first resonator 42 within the shiftregister, I provide a frequency divider 50 having an input connected toclock 45. Frequency divider 50 is effective for intermittently producingsignals, each of which is a first subharmonic of the signals produced byclock 45. In other words, divider 5t) produces signals at half thefrequency of clock 45 and in substantial coincidence with twoconsecutive complete signals produced by clock 45. The output signals ofdivider 50 are applied to the primary of transformer 51. The righthand,secondary winding of transformer 51 is tapped to ground, the signalsappearing at its lower terminal being 180 degrees out-of-phase with thesignals represented in Fig. 3e appearing at its upper terminal andconductor 60. The lower winding terminal signals may be passed throughother apparatus (not shown) which is eective for passing signals toconductor 59 during the times that exciting signals are present onconductor 48. Such signals are represented in Fig. 3d. It is to beunderstood that the signal chopping apparatus is not strictly necessaryto the functioning of the apparatus used to practice my invention, butis included in order to make it easier for the reader to understand theoperation of the apparatus.

From the above considerations,.it is` to be seen that divider 50 can beregarded as being equivalent to first and second signal generators whichare operative for producing 1r and intermittent 0 phase signals onconductors 60 and 59, respectively. Divider 50 is further arrangedrangement, each of resonators S2, 53 and 54 produces at' theaforementioned 'second inputs of resonators 42, 43v

or 44, I provide gates 55, 56 and 57. Each gate of gates 55, 56 and 57has a control input, 55a, 56a and 57a, respectively, and is operative inresponse to the application of a signal thereto for making the gate passsignals from the corresponding one of resonators 52, 53 and 54 to theappropriate one of second signal input of gates 42, 43 and 44. Theapplication of a "1 signal at double strength to the second input of anyof stages 42, 43 or 44 in coincidence with the application of a normalstrength "0 signal to the first input of any one of resonators 42, 43 or44 at a time that an exciting signal is applied to the exciting input ofthe same resonator is effective for causing the resonator to produce a loutput signal, rather than the normal 0 signal. As in the case of "0signals, a l signal produced and temporarily stored in any one ofresonators 42, 43 or 44 is shifted through the succeeding stages of theshift register and appears ultimately as a l signal on output 44b ofresonator 44 for utilization in succeeding equipment (not shown).

In order to control gates 55, 56 and 57, I provide means for couplingthe output conductor 41a of multivibrator 41 to each of control inputsa, 56a and 57d of gates 55, 56 and 57, respectively. With thisarrangement, the appearance of a signal on conductor 41a at any instantin time must coincide at a time when at least one of resonators 52, 53or 54 is excited. As a result, a 1r phase signal from the concurrentlyexcited one of resonators 52, 53 and 54 passes into the one of shiftregister resonators 42, 43 or 44 which is to be next excited.

While the simultaneous enabling of gates 55 and 56 or of gates 56 and 57at a time when both resonators 52 andy 53 or both resonators 53 and 54are excited is without effect other than to admit a 1r phase signal tothe second inputs of resonators 42 and 43 or to the inputs of resonators43 and 44. Such simultaneous input of 1r phase signals to either of theaforementioned pairs of resonators must occur at a time when the oneresonator of the pair closer to divider 50 in the series of shiftregister resonators has already been set to producing a 0 signaLtheapplication of the 1r phase signal to the latter resonator is withouteffect, and the 1r phase signal is produced only in the one of theaforementioned resonator pairs remote from so that the 0" phase signalon conductor 59 are substantially equal to the amplitude of signalsproduced by resonators 42, 43 and 44.

The 0 signals from voltage divider 5G which are represented in Fig. 3d,are coupled directly to the rst input 42a of resonator 42, so thatthecontinuing O signals applied to resonator 42 are shifted through thevarious resonator stages and normally appear atoutput 44h of lastresonator 44 in the register. Thus far, the operation described isbasically similar to that described in the aforementioned Goto paper asa normal or three-step parametric excitation.

Upon the occurrence of a signal on conductor 41a, it is desired to causethe excited one of the register stages to transmit a 1r phase signalinstead of the normal 0 signal. Accordingly, I provide means includingparametrically-excited resonators 52, 53 and 54 for supplying 1r phasesignals to second inputs 42e, 43e and 44e of resonators 42, 43 and 44,respectively. l Each of resonators 52, 53 and 54 has a signal inputl52a, 53a and 54a coupled to the upper secondary winding terminal oftransformer 51. Resonators 52, 53 and 54 also include exciting inputs52b, 53b and 54b, respectively, connected to conductors 47, 48 and 49,respectively. With this arment of my invention, other modifications willreadilyA divider 50 in the series of shift register resonators. However,the simultaneous enabling of gates 57 and 55 by a pulse on conductor 4tawhich overlaps in time the excitation signals on conductors 47 and 49could result in the transmission of two separate output signals, sinceit would be possible to set both resonators 44 and 42 to producing 1rphase signals at separate times. In order to prevent such a doubleoutput signal, I provide means including inverter 58 for coupling theoutput of gate 57 to a second input 52d of'resonator 52. Inverter 5S iseffective for supplying ,to input 52d a signal substantially the sameamplitude but degrees out-of-phase with the input signal applied toinput52a of that same resonator.

Consequently, the input signals applied to the inputs lof` resonator 52cancel each other, and resonator 52 is made incapable of producingsignals for application to resonator 42 during the interval thatresonator 54 is supplying a signal to resonator 44 of the shiftregister.

While I have shown and described a specic embodi- Voccur to thoseskilled in the art." I do not therefore v7 claimsto cover all suchmodifiactions falling withinv the spirit and scope of my invention.

`What is claimedis:

V 1. In a system for phasing signals emanating from a source capable ofproducing signals of uniform duration at random times; a shift registercomprising a plurality of memory elements disposed in a series; each ofsaid elements having a first signal input, an excitinginput, and anoutput and each of the intermediate and last of s aid elements in saidseries having a second signal input; said output of each of the rst andintermediate said f elements in said series being coupled to said secondsignal input Of the next succeeding one of said elements in said series;said output of the last of said elementsin said series constituting anoutput for said register; each of said elements ybeing operative inresponse to the coincident application of a signal to oneof said signalinputs and to said exciting input for producing a signal lon said outputfor the duration of the signal applied to said exciting input; drivingmeans operative for repetitivelyv applying signals of at least the sameduration as the signals produced from said random time signal source insequence to said exciting input of each of said elements in the order ofoccurrence of said elements in said series in order to advance a signalstored within any one of said elements to said register output; aplurality of signal producing means, each of said signal producing meansbeing individual to a particular one of said elements; each of said,signal producing means being operative for producing signals incoincidence with signals applied to said exciting input of thecorresponding one of said register elements; a plurality` of gates,-eaclr of said gates being individual to a particular one of said signalproducing means and having a control input; each of said gates beingoperative in response to the application of a signal applied to saidcontrol input thereof for passing Signals therethrough; means includingthe corresponding one of said gates for individually coupling each ofsaid signal producing means to said first signal input of the next ofsaid elements in said series; and means for coupling said random signalsource to said control inputs of said gates; whereby the Production ofsignals by said random signal producing means allows the passage ofsignals from one of said signal producing means into the next succeedingone of said elements in s aid register, and the resulting signal storedtherein isV advanced to arrive at said register output in coincidencewith the exciting signal applied to the last of said elements in saidregister.

t 2. In a system for phasing signals emanating from a source capable ofproducing signals of uniform duration at random times; a shift registercomprising a plurality of memory elements disposed in a series; each ofsaid elements having a first signal input, an exciting input, and anoutput, and each of the intermediate and last ofr said elements in saidseries having a second signal input; said output of each of the firstand intermediate said elements in said series being coupled to saidsecond signal input of the next succeeding one of said elements in saidseries; said output of the last of said elements in said seriesconstituting an output for. said register; each of said elements beingoperative in response to the coincident application of avsignal to oneof said signal inputs and to said exciting input for producing a signalon said output for the duration of the signal applied to said excitinginput; driving means operative for repetitively applying signals of atleast the same duration as the signals produced froml said random timesignal source in sequence to said exciting input of each of saidelements in the order of occurrence of saidelementsV in said series inorder-to advance a signal stored within any one of said elements to saidregister output; a plurality of signal each of said signal producingmeans being 4operative in response to the coincident application ofsignals to said signal and said exciting inputs thereof for producingsignals on said output thereof; means for applying'to each of saidsignal producing means exciting signals in coincidence with signalsapplied to said exciting input of the corresponding one of said registerelements; means for applying signals to each of said signal producingmeans; signal input in coincidence with signals applied to said excitinginput thereof; a plurality of gates, each of said gates being individualto a particular one of said signal producing means and having a controlinput; each of said gates being operative in response to the application of a signal applied to said control input thereof for passingsignals therethrough; means including said gatesv for coupling saidoutputs of the corresponding ones lof said signal producing means tosaid first signal input of the next of said elements in said series; andmeans for coupling said random signal source to said control inputs ofsaid gates; whereby the production of signals by said random signalproducing means allows the passage of signalsfrom one of said signalproducing means into the next succeeding one of said elements in saidregister, and the resulting signal stored in that one of said elementsis advanced to arrive at said register output in coincidence with theexciting signal applied to the last `of said elements in said register.

3. In a system for phasing signals emanating from a source capable ofproducing signals of uniform duration at random times; a shift registercomprising a plurality of substantially identical memory elementsdisposedin ay series; each of said elements having first and secondsignal inputs, an exciting input, and an output; said output of each ofthe first and intermediate of said elements in said series being coupledto said second signal input of the next succeeding one of said elementsin said series,l said output of the last of said elements in said seriesconstituting an output for said register; each of said elements beingoperative in response to the coincident application of a signal to saidexciting input and signals of particular characteristics to said signalinputs for producing for the duration of the signal applied to saidexciting input on said output a signal having the same characteristicsas the one of the signals applied to said inputs having greateramplitude; driving means operative for repetitively applying signals ofat least the same duration as signals produced by said random timesignal source in sequence to said exciting input of each of saidelements in the order of occurrence of said elements in said seriesv inorder to advance a signal stored within any one of said elements to saidregister output; a first generator` operative for applying to saidsecond signal input of the first of said series elements signals offirst characteristic substantially in coincidence with signals appliedto said exciting input of the first of said register elements and ofamplitude substantially equal to signals produced at said outputs ofsaid memory elements; a second generator operative for producing signalsof a second characteristic in coincidence with cach signal produced bysaiddriving means; a plurality of signal producing means; each of saidsignal producing means corresponding to one of said register elementsand having an input coupled to said second generator, an exciting inputproducing means; each of said signalproducing means coupled in parallelwith said exciting input of the corresponding one of said registerelements, and an output; each of said signal producing means beingoperative in response to the application of a signal to said excitinginput thereof and to the coincident application of?y a signal of aparticular characteristic to said signal input thereof for producing asignal of the same characteristic and of amplitude substantially greaterthan signals produced lby said first generator and saidjregister elements at said output thereof for the durationV ofj'the signal .appliedto said exciting input thereof; aplurality ogates, each ofrsa-id` gatescorrespondingto a particu' i d lar one of saidsignal producing means;each of said' gates having a control input and being operative inresponse to the application of a signal thereto for passing a signalfrom said output of the corresponding one of said signal producing meansto said first signal input of the next succeeding one of said elementsin said series of register elements; and means for coupling said randomVtime signal source to said control inputs of said gates; whereby saidshift register is normally eective for producing at said output a signalof first characteristic produced -by said first generator in coincidencewith signals applied to said exciting input of the last of said registerelements in said series, and is operative upon the appearance yof asignal on the output of said random time signal source for causing saidregister to substitute for the normal signal on said register output asignal of the character produced by said second generator which arrivesat said register output in coincidence with the nextoccurring signalapplied to exciting input of the last of said register elements.

4. The system set forth in claim 3 and having in ad dition: means forcoupling said output of said third signal producing means to said firstsignal producing means and `operative in response to the coincidentapplication of input signals to said first and said third signalproducing means for canceling signals at the output of said first signalproducing means; whereby the production of a double signal at the outputof said register is prevented.

5. In a system for phasing signals emanating from a source capable ofproducing signals of uniform duration at random times; a shift registercomprising first, second and third memory elements disposed in a series;each of said elements having a first signal input, an exciting input,and an output; each of the intermediate and last of said elements insaid series having a second signal input, said output of each of saidfirst and said second elements being coupled to said second signal inputof said second and said third element, respectively, and said output ofsaid third element constituting an output for said register; each ofsaid elements being operative in response to the coincident applicationof a signal to one of said signal inputs and to said exciting input forproducing a signal on said output for the duration of the signal appliedto said exciting input; driving means operative for repetitivelyapplying signals of the same or Y longer duration than signals producedby said random time signal source in sequence to said exciting inputs ofsaid first, said second and said third elements in the order named inorder to advance a signal stored within any one of said elements tosaid'register output; first, second and third signal producing meansindividual to said tirst, said second and said third register elements,respectively; each of said signal producing means being operative forproducing signals in coincidence with signals applied to said excitinginput of the corresponding one of said elements; first, second and'thirdgates for coupling said first, said second and said third signalproducing means to said first signal input of said second, said third,and said first elements, respectively; each of said gates having Vacontrol input and being operative in response to the application of asignal thereto for passing signals therethrough; and means for couplingsaid random signal source to said control input of each of said gates;whereby the production of signals by said random signal producing meansallows the passage of signals from one of said signal producing meansinto the next succeeding one of vsaid elements in said register, and theresulting signals stored therein are advanced to arrive at said registeroutput in coincidence with the application of an exciting signal to saidthird element Vin said register.

6. In a system for phasing signals emanating from a source capable ofproducing signals of uniform duration at random times; a shift registercomprising first, second and third memory elements disposed in a series;each of said elements having a first signal input, an exciting input,and an output, each of the second and said third elements having asecond signal input; said output of said first and second elements beingcoupled to said second signal input of said second and said thirdelements,

respectively, and said output of said third element constituting 'anoutput for said register; each of said elements being operative inresponse to the coincident application of a signal to one of said signalinputs and to said exciting input for producing a signal on said outputfor the duration of the signal applied to said exciting input; drivingmeans operative for repetitively applying signals of the same or longerduration than signals produced by said random time signal source insequence to said exciting inputs of said rst, said second and said thirdelements in the order named in order to advance a signal stored withinany `one of said elements to said register output; first, second andthird signal producing means individual to said first, said second andsaid third register elements; each of said signal producing means havingsignal and exciting inputs and an output; each of said signal producingmeans being operative in response to the coincident application ofsignals to said signal and said exciting inputs for producing signals onsaid output thereof; means for coupling said exciting input of saidfirst, said second and said third elements to said exciting inputs ofsaid first, said second, and said third signal producing means,respectively; means for applying signals to said signal inputs of saidfirst, said second, and said third signal producing means in coincidencewith signals applied to said exciting inputs there-- of; first,secondand third gates for coupling said output of said first, saidsecond and said third signal producing means to said first signal inputof said second, said third and said first elements, respectively; eachof said gates having a control input and being operative in response tothe application of a signal thereto for passing signals therethrough;and means for coupling said random time signal source to said controlinput of each of said gates; whereby the production of signals by saidrandom signal producing means allows the passage of signals from one ofsaid signal producing means into the next succeeding one of saidelements in said register, and the resulting signals stored therein areadvanced to arrive at said register output in coincidence with theapplicationof signals to said third element in said register.

7. In a system for phasing signals emanating from a source capable ofproducing signals of uniform duration at random times; a shift registercomprising first, second,

and third, substantially identical memory elements dis-1 posed in aseries; each of said elements having first and second signal inputs, anexciting input, and an output; said output of each of the first and saidsecond elements in said series being coupled to said second signal inputof the next succeeding one of said elements in said series', and saidoutput of the last of said elements in said series constituting anoutput for said register; each of said elements being operative inresponse to the application of a signal to said exciting input and tothe coincident application of signals of particular characteristics tosaid vsignal inputs for producing on said output thereof a signal ofcharacteristic similar to the one of the signals applied to said inputsthereof having the greater amplitude for the duration of the signalapplied to said exciting input; driving means operative for repetitivelyapplying signals of the same or longer duration than the signalsproduced by said random time signall source in sequence to said excitinginput of each of said elements in the' order of occurrence of saidelements in said series in order to advance a signal stored withinanyone of said l elements to said register output; a first generatoreffective for producing signals of a first characteristic substantiallyin coincidence with signals applied to said exciting input of said firstregister element and of substantially sarneiamplitude as signalsproduced by any of said elements at the output thereof; a secondgenerator operative for producing signals of a second naturesubstantially in coincidence with signals produced by said driving meansand applied to said exciting inputs of the various ones of said registerelements; tiret, second and third signal producing means individual tosaid first, said second and said third elements, respectively; each ofsaid signal producing means having a signal input coupled to said secondgenerator, an exciting input coupled to said exciting input of thecorresponding one of said register elements, and an output; each of saidsignal producing means being operative in response to the application ofa signal to said exciting input and to the coincident application of asignal of particular characteristic to said signal input thereof forproducing signals of the same characteristic and of amplitudesubstantially greater than the amplirude of signals produced by saidfirst generator and any of said register elements, at said outputthereof; rst, second and third gates, each of said gates having acontrol input and being operative in response to the application of asignal thereto for passing signals therethrough; said first, said secondand said third gates being operative for passing signals from saidoutput of said first, said second and said third signal producing meansto said tirst signal input of said second, said iirst, and said thirdelements, respectively; and means for coupling said control inputs ofsaid gates to said random time signal producing means; whereby saidshift register is normally cifcctivefor producing at said registeroutput a signal of the character produced by` said first generator incoincidence with signals applied to said exciting input of said thirdregister element, and is operative upon the appearance of a signal onthe output of said random time signal source Vfor causing said registerto substitute for the normal signal a signal of the character producedby said second generator on said register output in coincidence with thenext-occurring excitation signal applied to said last register element.

S. The system set forth in claim 7 and having in addition: means forcoupling said output of said third signal producing means to said firstsignal producing ymeans and operative in response to the coincidentapplication of input signals to said iirst and said third signalproducing means for canceling signals at the output of said rst signalproducing means; whereby the production of a double signal at the outputof said register is prevented.

9. In a system for phasing signals emanating from a source capable ofproducing signals of uniform duration at random times; a shift registercomprising substantially identical first, second and thirdparametrically-excited resonators disposed in. a series; each of saidresonators having a first signal input, an exciting input, and anoutput; each of the intermediate and last of said resonators in saidseries having a second signal input, said output:

of each of said first and said second resonators being coupled to saidsecond signal input of said second and said third element, respectively,and said output of said third resonator constituting an output for saidregister; each of said resonators having a tank circuit connected ytosaid output thereof and being operative in response to the coincidentapplication of a signal at the resonant frequency of said tank circuitto one of said signal inputs and to said exciting input at double theresonant frequency of said tank. circuit for producing asignal at theresonant-frequency of said tank circuit on said output for the durationof the signal applied to said exciting input; driving means operativefor repetitively applying signals at double the resonant frequency ofsaid resonator circuits and of the same or longer duration than signalsproduced by said random time signal source in sequence to said excitinginputs of said first, said second and Vsaid third resonatorstin theorder named in order to advance a signalstored' within any one of saidresonators tQSaidmcgiSter output; first, second andthird signal pro- 'i2ducing .means individual to said first,Y said second and said thirdregister resonators, respectively; each of said signal vproducing meansbeing operative for producing signals at the resonant frequency of saidtank circuits in said resonators and in coincidence with signals appliedto said exciting input of the corresponding one of said resonators;first, second and rthird gates for coupling said first, said second andsaid third signal producing means to said first signal input of saidsecond, said third, and said iirst resonators, respectively; each ofsaid gates having a control input and being operative in response to theapplication of a signal thereto for passing signals therethrough; andmeans for coupling said random signal source to said control input ofeach of said gates; whereby the production of signals by said randomsignal producing means allows the passage of signals from one of saidsignal producing means into the next succeeding one of said resonatorsin said register, and the resulting signais stored therein are advancedto arrive at said register output in coincidence with thc application ofan exciting signal to said third resonator in said register.

l0. In a system for phasing signals emanating from a source capable ofproducing signals of uniform duration at random times; a shift registercomprising substantially identical rst, second and third memoryparametricallyexcited resonators disposed in a series; each of saidresonators having a first signal input, an exciting input, and anoutput, each of the second and said third resonators having a secondsignal input; said output of said first and said. second resonatorsbeing coupled to said second signal input of said second and said thirdresonators, respectively, and said output of said third resonatorconstituting an output for said register; each of said resonators havinga tank circuit and being operative response to the coincidentapplication of a signal at the resonant frequency of said tank circuitthereof to one of said signal inputs and a signal at double the resonantfrequency of said tank circuit thereof to said exciting input forproducing a signal at the resonant frequency of said tank circuit onsaid output for the duration of the signal applied to said exciting.input; driving means operative for repetitively applying signals atdouble the resonant frequency of said resonator tank circuits and of thesame or longer duration than signals produced by said random time signalsource in sequence to said exciting inputs of said first, said secondand said third resonators in the order named in order to advance asignal stored within any one of said resonators to said register output;a second group of resonators including fourth, fth and sixthparametricallyexcited resonators individual to said first, said secondand said third register elements, respectively; each of said secondgroup resonators having signal and exciting inputs and an output; eachof said second group resonators including a tank circuit substantiallyidentical to said tank circuits of said register resonators and beingoperative in response to the coincident application of a signal at theresonant frequency of said tank circuit thereof to said signalinput-andto asignal at double the resonant frequency of said tankcircuit thereof to said exciting input for producing a signal at theresonant frequency of said tank circuit on said output thereof; meansfor coupling said exciting input of said first, said second and saidthird resonators to said exciting inputs of said fourth, said fifth, andsaid sixth resonators, respectively; means for applying signals to saidsignal inputs of said second group resonators in coincidence withsignals'applied to said exciting inputs thereof; first, second and thirdgates for coupling said output'of said fourth, said fifth, and saidsixth signal producing means to said first signal input of said second,said third and said first resonators, respectively; each of said gateshaving a control input and being operative in response to theapplication of a signal thereto for passing signals therethrough: andmeans for coupling said random time signal source to said control inputof each of said gates; whereby the production of signals by said randomsignal producing means allows the passage of signals from one of saidsecond group resonators into the next succeeding one of said resonatorsin said register, and the resulting signals stored therein are advancedto arrive at said register output in coincidence with the application ofsignals to said third resonator in said register.

11. In a system for phasingsignals emanating from a source capable ofproducing signals of uniform duration at random times; a shift registercomprising first, second, and third substantially identicalparametrically-excited resonators disposed in a series; cach of saidresonators having first and second signal inputs, an exciting input, andan output; said output of said first and said second resonators in saidseries being'coupled to said second signal input of said second and saidthird resonators, respectively, and said output of said third resonatorin said series constituting an output for said register; each of saidresonators having a tank circuit and being operative in response to theapplication of a signal at double the resonant frequency of said tankcircuit to said exciting input and to the coincident application ofsignals at the resonant frequency of said tank circuit in particularphase relationships to the'signal applied to said exciting input` toboth said signal inputs for producing on said output thereof a signal offixed amplitude at the resonant frequency of saidtank circuit and thesame phase relationship to said signal applied to said exciting input'asthe signals applied to said inputs thereof having the greater amplitudefor the duration of the signal applied to said exciting input; drivingmeans operative for repetitively applying signals in phase with eachother at double the resonant frequency of said tank circuits and of thesame or longer duration than the signals produced by said random timesignal source in sequence to said exciting input of each of saidresonators in the order of occurrence of said resonators in said seriesin order to advance a signal stored within any one 'of said resonatorsto saidfregister output; a first generator effective for producingsignals in a particular constant phase relationship with signalsproduced by said driving means and substantially in coincidence withsignals applied to said exciting input of said first register resonatorand kof substantially the same amplitude as signals produced by any ofsaid resonators at the output thereof; a second generator operative forproducing signals at the resonant frequency of said tank circuits and180 degrees out-of-phase with signals produced by said first generatorsubstantially in coincidence with signals produced by said driving meansand applied to said exciting inputs of the various ones of said registerelements; a second group including fourth, fifth, and sixthparametrically-excited resonators individual to said first, said secondand said third resonators, respectively; each of said second groupresonators having a signal input coupled to said second generator, anexciting input coupled to said exciting input of the corresponding oneof said register elements, and an output; each of said second groupresonators including a tank circuit substantially identical to said tankcircuits of said register resonators and being operative in response tothe application of a signal at double lthe exciting frequency of saidtank circuits to said exciting input and to the coincident applicationof a signal at the resonant frequency in particular phase relationshipto the signal applied to said exciting input to said signal inputthereof for producing signals at said output thereof in the samerelationship to the said exciting input signal and of amplitudesubstantially greater than the amplitude of signals produced by saidfirst generator and said register resonators; first, second and thirdgates, each of said gates having a control input and being operative inresponse to the application of a signal thereto for passing signalstherethrough; said first, said second and said third gates beingoperative for passing signals from said output of said fourth, said fth,and said sixth resonators to said first signal input of said and meansfor coupling said control inputs of said gates to said random timesignal producing means; whereby said v shift register is normallyeffective for producing at said register output a signal in phase withthe signal produced by said first generator and in coincidence withsignals applied to said exciting input of said first register resonator,and is operative upon the appearance of a signal on the output of saidrandom time signal source for causing said register to substitute forthe normal signal on said register output a signal degrees out-of-phasewith the normal signal and in coincidence with the next-occurringexcitation signal applied to said last register resonator.

l2. The system set forth in claim 11 and having in addition: an inverterhaving an input and an output operative in response to the applicationof signals torsaid input at a particular amplitude for producing at saidoutput signals at the same amplitude and 180 degrees out-of-phase withsignals applied to said input;'and said fourth, second group resonatoralso includes a second signal input, said fourth resonator beingoperative in response to the application of coincident signals to saidsignal inputs at the resonant frequency of said tank circuit and to saidexciting input at double the resonant frequency of said tank circuit forproducing on said output of said' fourth resonator a signal at theresonant frequency of said tank circuit and at the amplitude of the ,sumof the signals applied to said signal inputs thereof; and wherein saidinverterinput is coupled to said sixth resonator output, and saidinverter output is coupled to said second input of said fourthresonator; whereby said signals applied to said signal inputs of saidfourth resonator are canceled when said fourth and said sixth resonatorsare coincidentally excited, and a double output signal in said registeris thereby prevented.

No references cited.

